一种弱溶蚀酸液在砂岩储层酸化中的应用研究

STUDY AND APPLICATION OF A WEAK CORROSION ACID FOR SANDSTONE ACIDIZING

为避免触发酸化储层改造中使用强溶蚀酸液体系造成的二次伤害和储层出砂,通过酸-岩溶蚀能力、抑制二次沉淀、天然岩心酸化模拟和单轴抗压分析研究了一种弱溶蚀酸液体系。该酸液体系溶蚀能力只有常规土酸酸液溶蚀能力的30%左右,对各种二次沉淀物质抑制能力均强于标准土酸。弱溶蚀酸液处理后岩心抗压强度下降率为土酸处理后的35.4%,综合酸化性能评价实验中弱溶蚀酸液体系能将被污染的岩心渗透率恢复到107.1%。弱溶蚀酸液体系实际应用海西部某油田某井W_(3)段Ⅵ、Ⅶ_(上)、Ⅶ_(下)油组砂岩储层,恢复该井产能且增油133.28 m^(3)/d,后期生产过程中未出现二次伤害和储层出砂,取得良好酸化增产效果。

In order to avoid the secondary damage and sand production caused by the use of strong corrosion acid solution system in triggering acidification reservoir reconstruction,a weak corrosion acid solution system was studied through acid-rock corrosion ability,inhibition of secondary precipitation,natural core acidification simulation and uniaxial compression analysis.The corrosion capacity of the acid solution system was only about 30%of that of the conventional soil acid solution,and the inhibition capacity of the acid solution system on various secondary precipitation substances was stronger than that of the standard soil acid.The decrease rate of core compressive strength after weak corrosion acid treatment was 35.4%of that after soil acid treatment.In the comprehensive plugging performance evaluation experiment,the weak corrosion acid solution system could restore the permeability of contaminated core to 107.1%.Weakly dissolved acid system was applied to sandstone reservoir ofⅥ,Ⅶupper andⅦlower oil groups in W_(3) member of a well in an oilfield in western Hai.The productivity of the well was restored and the oil production was increased by 133.28 m^(3)/d.There was no secondary damage and sand production in the later production process,and good acid stimulation effect was achieved.